This is the IP address identifying the source (originating) endpoint of this circuit, one half of the pair (with circuitDestIpAddr) that defines the two ends a point-to-point circuit connects. An admin provisioning a new circuit sets this to the address of the local or originating chassis/interface so the circuit's path can be established and later matched against circuitFailLocIpAddr if something breaks at that end. For example, if this circuit connects two ring nodes, setting this to 10.5.0.1 designates that node as the circuit's source side for all subsequent endpoint-specific configuration and fault reporting.